Gregus-type common fixed point theorems for tangential multivalued mappings of integral type in metric spaces

Abstract

The concept of tangential for single-valued mappings is extended to multivalued mappings and used to prove the existence of a common fixed point theorem of Gregus type for four mappings satisfying a strict general contractive condition of integral type. Consequently, several known fixed point results generalized and improved the corresponding recent result of Pathak and Shahzad (2009) and many authors. Copyright 2011 W. Sintunavarat and P. Kumam.